Maternal endometrial oedema may increase perinatal mortality of cloned and transgenic piglets.

The perinatal mortality of cloned animals is a well-known problem. In the present retrospective study, we report on mortality of cloned transgenic or non-transgenic piglets produced as part of several investigations. Large White (LW) sows (n = 105) received hand-made cloned LW or minipig blastocysts and delivered either spontaneously or after prostaglandin induction followed by either Caesarean section or vaginal birth. The overall pregnancy rate was 62%, with 26% of pregnancies terminating before term. This resulted in 48 deliveries. The terminated pregnancies consisted of 12 abortions that occurred at 35 ± 2 days gestation and five sows that went to term without returning to heat and then by surgery showed the uterus without fetal content. The gestation length was for sows with LW piglets that delivered by Caesarean section or vaginally was 115.7 ± 0.3 and 117.6 ± 0.4 days, respectively. In sows with minipiglets, the gestation length for those delivered by Caesarean section or vaginally 114.4 ± 0.2 and 115.5 ± 0.3 days, respectively. Of the 34 sows that delivered vaginally, 28 gave birth after induction, whereas 6 farrowed spontaneously. Of the 14 sows that delivered after Caesarean section and in the five empty sows, the endometrium and placenta showed severe oedema. Piglet mortality following vaginal delivery was higher than after Caesarean section (31% v. 10%, respectively; P < 0.001). When vaginal delivery occurred spontaneously, the stillborn rate was greater than after induced delivery (56% v. 24%, respectively; P < 0.0001). Internal organ weights were recorded for seven cloned LW piglets and six normal piglets. The relative weight of the heart, liver, kidneys and small intestine was found to be reduced in the cloned piglets (P < 0.05). The present study demonstrates extensive endometrial oedema in sows pregnant with cloned and transgenic piglets, as well as in empty recipients, at term. The growth of certain organs in some of the cloned piglets was reduced and the rate of stillborn piglets was greater in cloned and transgenic piglets delivered vaginally, possibly because of oedema of the fetal-maternal interface.

IFPA meeting 2008 workshops report.

Workshops are an important part of the IFPA annual meeting. At the IFPA meeting 2008 diverse topics were discussed in 12 themed workshops. Topics covered included: immunology of placentation; galectins and trophoblast invasion; signaling in implantation and invasion; markers to identify trophoblast subpopulations; placental pathology; placental toxicology; stereology; placental transport of fatty acids; placental mesenchymal stem cells; comparative placentation; trophoblast and neoplasia; trophoblast differentiation. This report is a summary of the various topics covered.

Ultrastructure and electrolyte transport of the epithelium of coprodeum, colon and the proctodeal diverticulum of Rhea americana.

The structure and function of the lower intestinal tract of Rhea americana were characterized to evaluate the evolutionary relationship to other struthioniform and avian species. In 5 rheas the gross anatomy and the light and transmission electron microscopy were studied in parallel to in vitro electrophysiological measurements of ion transport. The mucosa in the colon was amplified with villi, often branched, and in the coprodeum with folds. In both tissues the epithelium was a monolayer composed of columnar absorptive cells, goblet cells and mitochondria-rich cells. Colon and coprodeum appeared to produce large amounts of mucus. The proctodeal diverticulum was rich in lymphoid tissue arranged into lobuli bursales, and it was concluded that this structure is a modified bursa of Fabricius. The sparse interlobular epithelium of the diverticulum resembled that of colon and coprodeum. Baseline short circuit currents (I(SC)) averaged 114.5+/-13.8 microA/cm(2) in colon, 193.1+/-30.3 microA/cm(2) in coprodeum and 60.4+/-9.1 microA/cm(2) in the diverticulum. Amiloride sensitive Na+-transport amounted to 31, 88 and 38% of the baseline I(SC) in these three tissues, respectively. In all tissues, there was also a modest, theophylline activated chloride secretion response, and ouabain, the Na+/K+-ATPase inhibitor, abolished most of the I(SC). The transepithelial resistance (TER) of the diverticulum was much higher than the other tissues. Upon dissection, urate from ureteral urine was observed in the lower third of the colon and to a lesser extent in the proctodeal diverticulum, indicating retrograde peristalsis of the urine. Thus, unlike the ostrich, there is no sphincter separating colon and coprodeum. On the other hand, a thick mucus layer was seen overlying the mucosa in both colon and coprodeum, as in the ostrich. This may help to prevent osmotic water loss, despite the presence of hyperosmotic urine (up to 800 mOsm) in the lower intestine. Both morphological and electrophysiological data from the rhea support the hypothesis that the rhea lower intestine contributes to post-renal modification of ureteral urine and to the regulation of osmotic balance, as also seen in domestic fowl and other avian species. The proctodeal diverticulum functions mainly as an immune organ, with only limited transport capability.

Glucose transporter 1 localisation throughout pregnancy in the carnivore placenta: light and electron microscope studies.

Glucose is one of the major fetal nutrients. Maternofetal transfer requires transport across the several placental membranes. This transfer is mediated by one or more of the fourteen known isoforms of glucose transporter. So far only Glucose Transporters 1 and 3 (GT1, GT3) have been shown to be located in placental membranes. GT1 may be the only one on the syncytiotrophoblast (human) or both may be present on the same membrane (rodents) or be required in sequence (ruminants, horses and elephant). This paper shows GT1 to be the only transporter demonstrable by immunocytochemistry in carnivore (cat, dog and mink) endotheliochorial placental membranes. GT1 is invariably present on both apical and basal surfaces of the cyto- and syncytiotrophoblast in all carnivore species examined and the pattern of development is described from implantation to term.

Macroscopic and microscopic aspects of collared peccary and white-lipped peccary placenta.

This study examines middle and late gestational placentae from 13 Tayassu tajacu (collared peccary) and 3 Tayassu pecari (white-lipped peccary), which are Artiodactyla belonging to the Family Tayassuidae. The chorionic sac of Tayassu species is diffuse and chorioallantoic. These epitheliochorial placentae show no trophoblast invasion into the uterine epithelium and there is interdigitation between fetal and maternal microvilli. Two distinct regions of the fetomaternal interface can be identified: the interareolar and the areolar regions. The uterine epithelium has eosinophilic cytoplasm with dispersed, basophilic and electron-dense granules. Trophoblast cells are irregularly cuboidal on top of the fetal ridges and columnar on troughs, where cells have cytoplasmic vesicles and large basal vacuoles, surrounded by whorls of smooth membranes. Capillaries indent the trophoblast cells forming a placental barrier 3 microm or less thick. The columnar uterine glandular epithelium has a subpopulation of granules staining with Perl's Prussian blue reaction, suggesting iron secretion. In areolar areas, the trophoblast cells show apical microvilli, a basophilic cytoplasm with electron-dense intracellular vacuoles and cisternae. The placenta can therefore be classified as non-deciduate. The ultrastructural aspects of this study reveal features that have not previously been described and extend our knowledge of functions relating to materno-fetal transport in these species.

Localization of vascular endothelial growth factor (VEGF) and its receptors VEGFR-1 and VEGFR-2 in bovine placentomes from implantation until term.

Interactions of vascular endothelial growth factor (VEGF) with its receptors VEGFR-1 and VEGFR-2 promoting angiogenesis have been described in placentation of human, mink and pig. The bovine placenta is multiplex, villous and synepitheliochorial due to migratory trophoblast giant cells (TGC). To determine the role of VEGF in bovine implantation and placentation, placentomes and interplacentomal areas from 33 cows from early implantation until near term were evaluated by immunohistochemistry. VEGF immunoreactivity was detected in fetal and maternal blood vessel tissues during implantation and throughout gestation, and in preimplantatory trophoblast cells and uterine epithelium. After implantation the immunoreaction was confined to TGC and uterine epithelium. An antibody against bovine VEGF revealed a strong reactivity in the stroma of maternal caruncular septa in early and mid-gestation, which distinctly decreased near term. In interplacentomal areas, VEGF was found in luminal and glandular epithelia as well as in trophoblast, with distinctly higher reactivity in giant cells. VEGFR-1 was observed in trophoblast and uterine epithelium around implantation. Later, in definite placentomes, VEGFR-1 was localized in TGC near the chorionic plate and in maternal endothelial cells in the center of the placentome. VEGFR-1 and VEGFR-2 were co-localized in uterine epithelium and trophoblast as well as in blood vessel tissue and uterine glands. The presence of VEGF, VEGFR-1 and VEGFR-2 at the feto-maternal interface and in vasculature indicates that in the bovine VEGF may have (1) classic functions in angiogenesis and vascular permeability, (2) growth factor properties, facilitating feto-maternal exchange via paracrine action, (3) chemotactic activity on capillary endothelium, and (4) an autocrine influence on TGC migratory activity.

Changes in endometrial ezrin and cytokeratin 18 expression during bovine implantation and in caruncular endometrial spheroids in vitro.

INTRODUCTION: The feto-maternal interface during bovine implantation was studied in vivo and using three-dimensional bovine endometrial (BCECph) and trophoblast spheroids (CCS), each with underlying fibroblasts. METHODS: The expression of ezrin and cytokeratin 18 (CK18) was analyzed via immunohistochemistry (IHC), RT-PCR and western blotting in bovine endometrium (GD 18-44) with in vivo (VIVO) and in vitro-produced embryos (VITRO). BCECph were stimulated with cotyledon-conditioned media (CCM) and analyzed by TEM/SEM and IHC. CCS were stained (IHC) for TGC markers, to test if spheroidal trophoblast cells had differentiated into TGC. RESULTS: At GD 20, caruncular epithelium (CE) and uterine glands (UG) showed a loss of cytosolic ezrin and CK18 followed by a complete loss of both proteins. At GD 35 both reappeared in CE and UG. The endometrial expression pattern did not differ between VIVO and VITRO. RT-PCR and western blotting confirmed the presence of ezrin and CK18. All spheroids had an outer polarized, cytokeratin and ezrin positive epithelium (CE or trophoblast) with apical microvilli. Stimulation of BCECph with CCM induced similar changes in ezrin expression as observed in endometrial tissue. However, no ultrastructural alterations were found by transmission electron microscopy. Absence of TGC-specific glycoproteins in CCS indicated that TGC differentiation was not induced by three-dimensional culture conditions. DISCUSSION: Ezrin and CK18 are downregulated during implantation in cattle. The expression changes represent a temporal depolarization, which could be important for an establishment of bovine pregnancy. Our in vitro experiments demonstrate that the trophoblast could contribute to this change in vivo.

Intracellular pathways of native iron in the maternal part of the porcine placenta.

In the diffuse epitheliochorial porcine placenta iron is secreted as uteroferrin by the maternal epithelium of the areola-gland subunit of the placenta. To elucidate the intracellular pathways of physiological iron in uterine gland epithelium material from 10 sows at 15 to 111 days of gestation was processed for electron microscopy by different routine methods with or without postfixation in osmium tetroxide. Ferritin particles were identified by their size and shape and the content of iron was confirmed by X-ray energy dispersive microanalysis of accumulated ferritin particles. Distinct ferritin particles were not observed in the extracellular space either basal to or luminal to the epithelial cells. Intracellular ferritin was observed apparently free in the cytoplasm, but in variable amounts. Transfer tubules and dense bodies were located basally in the secretory cells. Both of these organelles contained ferritin particles, showed reaction sites for acid phosphatase and were stained by periodic acid-thiocarbohydrazide-silver proteinate. The ciliated cells differed by having apically located dense bodies containing numerous ferritin particles. Our finding of native ferritin in cells with hormonally regulated iron transport supports the concept that transfer tubules as part of the lysosomal complex are part of the endocytic pathway in secretory cells and indicate that ferritin here is an intracellular transport or storage intermediate.

Gap junction pleiomorphism in the root system of the rhizocephalans (Arthropoda: Crustacea).

We have studied gap junctions in the root system of four different species of rhizocephalans (Arthropoda: Crustacea) using freeze-fracture. Numerous and often very extensive gap junctions are present between the root cells. They are of the characteristic E-type also found in other arthropods. Large junctional particles (ca. 13 nm) are located predominantly on the E-face, while complementary pits and a few dislocated particles are present on the P-face. The gap junctions show a remarkable pleiomorphism. Small macular gap junctions with rather densely packed particles, larger irregularly shaped gap junctions, often forming bands with intervening particle-free membrane domains, and gap junctions with widely dispersed particles are observed. These features are documented both in material after conventional preparation including glutaraldehyde fixation and glycerol cryoprotection and in material frozen directly in a nitrogen slush without any preceding preparation, and are discussed in relation to possible functional significance.

Vasoactive intestinal peptide and substance P-like immunoreactivities in the enteric nervous system of the pig correlate with the severity of pathological changes induced by Schistosoma japonicum.

Limited studies have shown that in intestinal schistosomosis, the enteric nervous tissue becomes inflamed, disrupted and destroyed by granulomas and peptides, amines and neurofilaments contents are altered. Therefore, immunoreactivities of vasoactive intestinal peptide and substance P were correlated to pathological lesions in the large intestine from pigs infected with Schistosoma japonicum. Ganglia situated within or near granulomas showed ganglionitis, and necrosis of neurons as well as infiltration by eosinophils, mast cells, lymphocytes, plasma cells, neutrophils and macrophages. The inner submucous and mucous plexuses were the most damaged. In all categories of inflamed areas, the vasoactive intestinal peptide-like immunoreactive was reduced in all plexuses whereas, that of substance P was increased both in the enteric nerve plexuses and enterochromaffin cells in lightly, moderately and severely inflamed tissues. However, both peptides were highly diminished or absent in very severe lesions and areas surrounding schistosome eggs and mature worms laying eggs in the submucosal veins. The alterations of the levels of vasoactive intestinal peptide and substance P were correlated with severity of inflammation. Our observations show alterations of vasoactive intestinal peptide and substance P contents in the local microenvironment in the vasoactive intestinal peptide- and substance P-mediated reflex pathways which regulate intestinal motility, epithelial transport and modulate immunity. These changes could cause alterations in bowel motility, electrolyte and fluid secretion, vascular and immune functions during S. japonicum infections in the pig. This may, therefore, partly play a role in the pathobiology of migration and egress of schistosome eggs as well as influence trapping of eggs in granulomas, and account for diarrhoea, loss of body weight and failure to thrive, which are recorded in schistosomosis.

An extensive lysosomal system in the maternal epithelium of the porcine placenta.

The material comprised 64 placentae from 19 Danish Landrace sows representing gestational stages from 16 to 112 days. The maternal epithelium was examined by means of light and electron microscopy to describe the morphology of the irregular electron-dense bodies and membrane whorls and their relation to gestational stages. Incubation for acid phosphatase demonstrated their lysosomal nature. Electron micrographs of serial sections followed by reconstructions and freeze-fracturing demonstrated their three-dimensional structure and relation to transfer tubules. In the early stages, during the development of fetal vascularization, the maternal epithelium was dominated by inclusions of lipids and glycogen, which can easily be transferred to and utilized by the embryo. The development of an extensive lysosomal system, consisting of irregular electron-dense bodies, membrane whorls and transfer tubules, indicates that cellular digestion is an important factor in the transfer and subsequent fetal utilization of maternal nutriments in the last two-thirds of gestation, and that this development is apparently related to anatomical and physiological changes during gestation.

Co-localization of vascular endothelial growth factor and its two receptors flt-1 and kdr in the mink placenta.

Placental angiogenesis plays an important role in placental development and morphogenesis. Vascular endothelial growth factor (VEGF) is a well-known angiogenic growth factor, which has previously been localized in different epitheliochorial and haemochorial placenta types. In the present study VEGF and its Flt-1(VEGFR-1) and KDR (VEGFR-2) receptors were immunolocalized in the endotheliochorial mink placenta throughout gestation. VEGF, Flt-1 and KDR co-localized to fetal and maternal microvascular endothelial cells, but with a temporal difference, displaying KDR in endothelial cells throughout gestation, whereas the VEGF and Flt-1 maternal endothelial cell staining was most intense during late gestation. Additionally, KDR was found in vascular related mesenchymal cells. The VEGF-receptors were also localized in non-endothelial cells, e.g. the uterine luminal and glandular epithelium as well as the trophoblast. Our results are in agreement with former studies, showing the different effects of the Flt-1-and KDR receptors in respect of angiogenesis. More importantly, the present study of the endotheliochorial placenta localizes the VEGF-ligand-receptor system in non-endothelial cells, and thereby strengthen the hypothesis that VEGF, apart from its well-established angiogenic properties, must also have additional functional roles in the establishment and development of the placenta.

An electron microscopic study of histiotrophe in the interareolar part of the porcine placenta.

Placentae from nine sows covering gestational stages from 33 to 112 days were examined by light and electron microscopy. Deeply stainable electron-dense histiotrophe was demonstrated in the interareolar placenta. Focal accumulations of cell debris with profiles of organelles were demonstrated in the intermicrovillous space between uterine epithelium and trophoblast. In addition, small expansions of amorphous histiotrophe were found between the microvilli. Furthermore, histiotrophe with profiles of cytomembranes was shown in intercellular spaces in columnar trophoblast between the microvillar border and tight junctions. Dense bodies were demonstrated in the uterine epithelium, and endocytic vesicles and branched tubular structures with dense contents were found in the columnar trophoblast. It is concluded that focal accumulations of cell debris are derived from degenerating epithelial cells in the endometrium and chorion, and that amorphous histiotrophe arises by secretory activity of uterine epithelium. It is further concluded that the histiotrophe is absorbed by columnar trophoblast of the chorionic fossae.

Immunohistochemical localization of vascular endothelial growth factor (VEGF) and its two specific receptors, Flt-1 and KDR, in the porcine placenta and non-pregnant uterus.

Placental angiogenesis and growth are crucial elements in embryonic and later fetal development. Vascular endothelial growth factor (VEGF) and its specific receptors Flt-1 (VEGFR-1) and KDR (VEGFR-2) compose potent ligand receptor systems involved in angiogenesis and microvascular hyperpermeability. In the present immunohistochemical study, VEGF, Flt-1 and KDR were localized in uterus of cyclic non-pregnant pigs and in the porcine epitheliochorial placenta throughout gestation. Emphasis was placed on early gestational stages, where morphological studies have demonstrated extensive angiogenesis during initial placentation. The results revealed a high correlation in spatiotemporal distribution between the ligand and its receptors and a surprising demonstration of VEGF receptors in several non-endothelial cells. In non-pregnant pigs, VEGF, Flt-1 and KDR exhibited moderate to intense staining in uterine luminal epithelium and smooth muscle cells of the vessel walls. Endothelial cells of arteries and arterioles revealed labelling for Flt-1 and KDR, whereas the uterine glandular epithelium displayed intense KDR immunoreactivity at the late luteal phase. During gestation the uterine luminal epithelium demonstrated weak ligand and receptor immunostaining in the first half of early gestation [< or = 21 days post coitus (p.c.)], whereas later stages (> or = 21 days p.c.) displayed intense immunolabelling. Endothelial cells, smooth muscle cells of the vessel walls and uterine glandular epithelium revealed intense ligand and receptor immunoreactivity throughout gestation. In the fetal part of the placenta, VEGF, Flt-1 and KDR immunostaining displayed moderate to intense reactivity in the trophoblast throughout gestation, except during the second half of early gestation (days 21-30 p.c.). Fetal vessel walls were also immunopositive for VEGF, Flt-1 and KDR. Taken together, the results imply that the VEGF, Flt-1 and KDR ligand receptor system participate in the regulations of porcine placentation and that it in addition to its angiogenic properties also may influence the cellular differentiation and transport capabilities in uterine luminal as well as glandular epithelium and the trophoblast.

Environmental pollutants as aetiological agents in female reproductive pathology: placental glycan expression in normal and polychlorinated biphenyl (PCB)-exposed mink (Mustela vison).

Polychlorinated biphenyls (PCB) may cause growth retardation or fetal death in mink. Pathological changes in endotheliochorial mink placentae were examined following exposure to PCB during gestation. Placentae from six animals with average fetal crown-rump (C-R) lengths between 16 and 53 mm given 0.65 mg/day Clophen A50 (low dose), and one from five animals with an average fetal C-R length of 14 mm given 1.3 mg/day (high dose), were examined. Mink were treated from 9 to 24 days before mating until killed at day 53. Placentae were formalin-fixed with four size-matched controls and embedded in resin. Sections were stained with five biotinylated lectins to detect specific glycans. Both control and treated (low dose) mink showed degenerative changes in maternal endothelium from 13-16 mm, revealed by increased lectin binding, caused probably by high cell turnover during tissue remodelling. Controls of 47 and 50 mm exhibited fewer degenerate maternal endothelial cells. The 31-mm PCB-treated tissue showed separation of the trophoblast from the interstitial layer and, at 53 mm, loss of its normal architecture, increased damage to maternal endothelium and infarction. High-dose PCB was extremely toxic, producing fetal death or extensive placental infarction by 14 mm C-R length. Lectin staining thus revealed the effects of PCB toxicity, shown by increased injury to maternal endothelium and severe trophoblastic damage.

High densities of angiotensin II subtype 2 (AT2) receptors in the porcine placenta and fetal membranes.

The present study was undertaken in order to characterize and determine angiotensin (Ang) II receptors and renin in the porcine placenta and fetal membranes. High densities of Ang II receptors of subtype 2 (AT2 receptors) were demonstrated in all parts of the placenta and fetal membranes throughout gestation. AT1 receptors (subtype 1) were only found in the first part of the gestation and only in the allantochorion-endometrium at low densities. The total Ang II receptor density was increased in the allantochorion-endometrium in the last stage of gestation. Except for this finding the Ang II receptor density did not vary during gestation. Some of the highest receptor densities were found in the allantoamnionic membrane. The Ang II receptor densities did not correlate with the duration of the gestation in any part of the placenta. Enzymatically active renin was found in all parts of the porcine placenta and fetal membranes in concentrations similar to those found earlier in the blood plasma. The renin concentrations did not correlate with the Ang II receptor densities or the duration of the gestation in any part of the placenta. Compared with the human placenta, where the Ang II receptors are almost exclusively AT1 receptors and low receptor densities are found in the fetal membranes, the present results indicate profound species differences in the expression and function of the renin-angiotensin system in the placenta and fetal membranes.

Perfusion in vivo of the porcine placenta. Fixation for EM.

A method for vascular perfusion in vivo, especially for EM fixation, was developed with the porcine placenta. The effect of fixation at varying parameters was studied. Nine multiparous Danish Landrace sows ranging in gestation from 33 to 112 days and in body weight from 160 to 257 kg were used. After general and local anaesthesia laparotomy was undertaken on the left flank and the uterine horn was perfused through a. uterina with buffered glutaraldehyde. Local perfusion through a. umbilicalis was undertaken in one case, and installation of concentrated glutaraldehyde into the allantoic cavity was performed in five cases. Perfusion-fixed and fresh tissue samples were fixed in OsO4 and processed for electron microscopy. The osmolarity of the buffer was varied between 470 and 660 mOsm. At high tonicity cytoplasm was well preserved but the intercellular spaces of the uterine epithelium was dilated. At about 575 mOsm the preservation was still good and the spaces were occluded. At lower tonicity damage occurred in the cytoplasm. The trophoblast was generally better preserved than the uterine epithelium. A rapid perfusion flow was beneficial for fixation.

Angiotensin-converting enzyme activity in the bovine uteroplacental unit changes in relation to the cycle and pregnancy.

The expression of the angiotensin-forming enzymes, renin and angiotensin-converting enzyme (ACE), were examined in the bovine uteroplacental unit. The ACE activity was determined in cell membrane fractions, and ACE and renin were localized by autoradiography and immunohistochemistry, respectively. In the myometrium, the ACE activity was significantly higher in dioestrous than in oestrous. ACE activity correlated negatively with the day of gestation in the endometrium and myometrium but positively in the placentome and allantoamniotic membrane. Autoradiography showed, that ACE was localized in vascular endothelial cells in all compartments. ACE was also expressed in the endometrial stroma and uterine glands, most pronounced in the outer part of the basal zone. In the intercotyledonary membrane and the placentome, the mesenchymal cells located near the trophoblast cells expressed ACE. Solitary macrophage- or monocyte-like cells showing intense renin immunoreactivity were found in the uterus, while the uterine and the glandular epithelial cells displayed inconsistent reactivity. No renin was observed in the placentomes or in the fetal membranes. The findings demonstrate a regulated expression of angiotensin-forming enzymes throughout the bovine uteroplacental unit. Whether this local renin-angiotensin system contributes to the highly regulated morphological and functional changes throughout the oestrous cycle and gestation remains to be established.

Placental glycosylation in peccary species and its relation to that of swine and dromedary.

Comparison has been made between glycans at the fetomaternal interface of two Tayassu species (New World peccaries or wild pigs) and those of swine (true pigs) and dromedary, which have similar epitheliochorial placentae. Plastic sections of near-term fetomaternal interface from Tayassu tajacu (120 days gestation) and Tayassu pecari (140 days gestation) were stained with 20 lectins and compared with those of swine (109 days) and dromedary (375 days). Both Tayassu species showed similar staining characteristics, which differed only slightly from those of the swine. Most differences were quantitative rather than qualitative, except for binding of Arachis hypogaea lectin to terminal beta-galactose which was absent in swine uterine epithelium though present in both Tayassu species, and binding of Sambucus nigra lectin to sialic acid which was absent in swine epithelium and trophoblast though present in Tayassu. Glycosylation of the dromedary fetomaternal interface showed, in contrast, significant differences compared to Tayassu and swine, particularly regarding fucosyl, sialyl and terminal galactosyl residues. Despite a divergence of between 33 million and 37 million years between true pigs and peccaries, glycosylation of the fetomaternal interface has remained similar, with most of the observed changes affecting terminal structures. The dromedary has an epitheliochorial placenta with a similar architecture, but different glycan expression, suggesting modification of glycosyl transferases with evolution. These data contain clues to changes of glycosyl transferase activity that accompany speciation.

Equine placental cup cells show glycan expression distinct from that of both chorionic girdle progenitor cells and early allantochorionic trophoblast of the placenta.

Using lectin histochemistry on plastic-embedded material, the glycosylation patterns of equine girdle and cup cells, and associated endometrial glands, have been investigated from 37 to 67 days gestation. Results were compared with the glycosylation of the 50-day allantochorionic trophoblast of the established equine placenta that will later form the microcotyledons. The differentiated cup cells, which secrete equine chorionic gonadotropin (eCG), showed a pattern of glycosylation that was distinct both from the progenitor girdle cells and the allantochorionic trophoblast, with granules that bound lectins indicating high levels of alpha2,6 and alpha2,3-linked sialic acid, N-acetyllactosamine and bi/tri antennary non-bisected and bisected complex N-glycan. This is consistent with the known carbohydrate content of eCG. In contrast, the allantochorionic trophoblast at 50 days lacked detectable amounts of sialic acid and showed high levels of tri/tetra-antennary non-bisected complex N-glycan and N-acetyl galactosamine which was absent in the cup cells. During the process of girdle cell migration into maternal tissues, the uterine glands became greatly enlarged and dilated basally, with increased amounts of glycosylated secretory products revealed by lectins, which often seeped out into the extracellular space via ruptures in the apical regions of the gland wall.